photodetector amplifier
Yea, thes is normal, then self most IT laser has some red light spectra too...
You must find a position & distance from your detector with maximum of signal, than fix it!
It will be better to apply a pigtail for so a measurement, then otherwise you will have to much changings/effects in your meas- setup, you will stangig to debag some dejustages...
K.
Added after 2 minutes:
You must be careful with Laser light/power_your eyes are irreparable! Is it a IR Laser or visible?